Two-dimensional carbon nanostructures: Fundamental properties, synthesis, characterization, and potential applications

Abstract

Since its discovery in less than five years ago, graphene has become one of the hottest frontiers in materials science and condensed matter physics, as evidenced by the exponential increase in number of publications in this field. Several reviews have already been published on this topic, focusing on single and multilayer graphene sheets. Here, we review the recent progresses in this field by extending the scope to various types of two-dimensional carbon nanostructures including graphene and free-standing carbon nanowalls/nanosheets. After a brief overview of the electronic properties of graphene, we focus on the synthesis, characterization and potential applications of these carbon nanostructures.

On the plasma-based growth of ‘flowing’ graphene sheets at atmospheric pressure conditions

“…Plasmas can ensure simultaneously high temperatures, highly reactive environment-electrons, ions, free radicals, energetic photons (UV radiation). For example, it has been shown that in plasma-enhanced chemical vapor deposition [1,3,5,7,9,10] a high level of control over material fluxes, heating and concomitantly the structure and properties of formulated materials can be achieved. This method makes use of a substrate inserted in a low-pressure plasma environment.…”

“…Carbon materials are of great interest for investigation and industrial activities owing to their abundance, stability and relative environmental friendliness [1][2][3][4]. Depending on the foreseen application, different carbon-based nanomaterials such as nanocrystals, fullerenes, carbon nanotubes (CNT), nanofibers, graphene, nanoribbons, and nanoflakes have been intensively investigated [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. CNTs discovery symbolizes a benchmark in nanoscience [14].…”

“…Recently many research groups shifted their research target towards graphene and related structures (graphene sheets, nanoribbons, carbon nanowalls etc) due to their extraordinary properties and enormous potential for applications [1][2][3][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The production of graphene requires specific conditions such as sufficiently high energy of the particles supplied to the growth zone and balanced influx of carbon particles.…”

Microwave plasmas applied for the synthesis of free standing graphene sheets

“…The generation of graphene oxide from graphite and the thermal reduction of the former is a second example of a top-down strategy; however despite rendering much higher yields, the method produces a highly defective product [7]. Bottom-up approaches include epitaxial growth, chemical vapour deposition (CVD) and vacuum graphitization of silicon carbide substrates, among others [2,[8][9][10]. The synthesis of graphene by CVD requires multiple processing steps, such as wet-etching and micro-fabrication, to obtain transferable sheets [8][9][10][11].…”

“…Graphene possesses many extraordinary properties [1,2], with potential applications in numerous scientific and engineering disciplines, including electronic devices, transparent conductive films, mechanical devices, chemical sensors, energy conversion and storage applications, etc [1][2][3][4][5][6].. Electrical, mechanical and optical performances of graphene crucially depend on its structural characteristics, i.e., number of monolayers, presence of sp 3 carbons, defects etc. Normally, the structural properties of nanostructures and, in particular, of grapheme, essentially depend on the assembly pathway.…”